title: Electrical stimulation via a biocompatible conductive polymer directs retinal progenitor cell differentiation.
abstract: The goal of this study was to simulate in vitro the spontaneous electrical wave activity associated with retinal development and investigate if such biometrically designed signals can enhance differentiation of mouse retinal progenitor cells (mRPC). To this end, we cultured cells on an electroconductive transplantable polymer, polypyrrole (PPy) and measured gene expression and morphology of the cells. Custom-made 8-well cell culture chambers were designed to accommodate PPy deposited onto indium tin oxide-coated (ITO) glass slides, with precise control of the PPy film thickness. mRPCs were isolated from post-natal day 1 (P1) green fluorescent protein positive (GFP+) mice, expanded, seeded onto PPY films, allowed to adhere for 24 hours, and then subjected to electrical stimulation (100 µA pulse trains, 5 s in duration, once per minute) for 4 days. Cultured cells and non-stimulated controls were processed for immunostaining and confocal analysis, and for RNA extraction and quantitative PCR. Stimulated cells expressed significantly higher levels of the early photoreceptor marker cone-rod homebox (CRX, the earliest known marker of photoreceptor identity), and protein kinase-C (PKC), and significantly lower levels of the glial fibrillary acidic protein (GFAP). Consistently, stimulated cells developed pronounced neuronal morphologies with significantly longer dendritic processes and larger cell bodies than non-stimulated controls. Taken together, the experimental evidence shows that the application of an electrical stimulation designed based on retinal development can be implemented to direct and enhance retinal differentiation of mRPCs, suggesting a role for biomimetic electrical stimulation in directing progenitor cells toward neural fates.
authors.forename: Rajiv
authors.initials: R
authors.lastname: Saigal
authors.forename: Elisa
authors.initials: E
authors.lastname: Cimetta
authors.forename: Nina
authors.initials: N
authors.lastname: Tandon
authors.forename: Jing
authors.initials: J
authors.lastname: Zhou
authors.forename: Robert
authors.initials: R
authors.lastname: Langer
authors.forename: Michael
authors.initials: M
authors.lastname: Young
authors.forename: Gordana
authors.initials: G
authors.lastname: Vunjak-Novakovic
authors.forename: Stephen
authors.initials: S
authors.lastname: Redenti
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry*; D002454:Cell Differentiation; D048429:Cell Size; D002478:Cells, Cultured; D004558:Electric Stimulation; D005455:Fluorescent Antibody Technique; D005904:Glial Fibrillary Acidic Protein / Q000235:genetics / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D016133:Polymerase Chain Reaction; D011108:Polymers / Q000737:chemistry*; D011493:Protein Kinase C / Q000235:genetics / Q000378:metabolism; D011758:Pyrroles / Q000737:chemistry*; D012160:Retina / Q000166:cytology*; D013234:Stem Cells / Q000166:cytology* / Q000378:metabolism; D017971:Tin Compounds / Q000737:chemistry; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism
chemical_list: D001672:Biocompatible Materials; D005904:Glial Fibrillary Acidic Protein; D018398:Homeodomain Proteins; D011108:Polymers; D011758:Pyrroles; D017971:Tin Compounds; D015534:Trans-Activators; C109288:cone rod homeobox protein; D049452:Green Fluorescent Proteins; C067635:polypyrrole; C109984:indium tin oxide; D011493:Protein Kinase C